Teens have taken a technology that was supposed to help grownups stop smoking and invented a new kind of bad habit, molded in their own image.

“Juul is already a massive public-health disaster—and without dramatic action it’s going to get much, much, much worse.”

Winickoff believes that the vape industry is co-opting the national wellness trend—“when, in fact, vaping can cause something called bronchiolitis obliterans, or popcorn lung,” he said. Popcorn lung has been linked to diacetyl, an organic compound that some companies use in their e-liquid, and that has been detected as a by-product of e-cigarette vapor. But diacetyl has also been detected in cigarette smoke, at a level hundreds of times greater, and no feasible amount of smoking has been found to cause popcorn lung. (Juul does not use diacetyl in its liquid, and, in tests, the company has found no measurable amounts of diacetyl in the vapor emitted by its devices.)